1. Field Of The Invention
This invention relates to a method for manufacturing a charge-coupled device (CCD) image sensor, more particularly to a method for manufacturing a hybrid circuit-type CCD image sensor.
2. Description Of The Related Art
A conventional method for manufacturing a CCD image sensor is shown in FIGS. 1 to 5. Referring to FIG. 1, a lead connecting frame 12 is provided on a ceramic base 16 by means of a sealing layer 18, made of a material such as glass, which is applied on the ceramic base 16. A window frame 14 is mounted on thee lead connecting frame 12 by means of another layer 18 of sealing material on a lower peripheral end of the window frame 14. The assembly of the window frame 14, the lead connecting frame 12 and the ceramic base 16 is then heated so as to melt the sealing layers 18 and bond together the lead connecting frame 12, the window frame 14 and the ceramic base 16.
Referring to FIG. 2, a CCD image sensor die 20 is mounted on the ceramic base 16 by applying a silver epoxy layer 22 on the ceramic base 16. A wire bonder (not shown) is then used to wire bond the bonding pads (not shown) on the image sensor die 20 to the bonding fingers (not shown) of the lead connecting frame 12 with the use of conductive wires 24.
Referring to FIG. 3, a glass lid 26 is mounted on the window frame 14 by applying a sealing epoxy layer 28 on an upper peripheral end of the window frame 14. The assembly of the glass lid 26, the lead connecting frame 12, the window frame 14 and the ceramic base 16 is heated in a dust-free oven so as to cure and harden the sealing epoxy layer 28 and bond together the glass lid 26 and the window frame 14 so as to form a CCD image sensor IC package. The package shown in FIG. 3 is a conventional ceramic dual-in-line IC package.
Referring to FIGS. 4 and 5, when in use, the aforementioned IC package is mounted on a first layout surface of an FR4 printed circuit board 30, the pins 121 of the lead connecting frame 12 extending through and being fixed in pin holes 301 of the printed circuit board 30. It is noted that a gap (t) of approximately 0.4 to 0.8 mm is formed between the ceramic base 16 and the printed circuit board 30, thereby increasing the height of the assembly of the package and the printed circuit board 30 to increase correspondingly the size of the assembly. Furthermore, the distance between each two adjacent pins 121 of the lead connecting frame 12 and the distance between each bonding finger of the lead connecting frame 12 and the corresponding bonding pad of the CCD image sensor die 20 are fixed in order to extend the pins 121 of the lead connecting frame 12 through the pin holes 301 of the printed circuit board 30, thereby hindering further reduction in the dimensions of the die 20. Additionally, due to the presence of the pin holes 301, discrete components 31, which are mounted on a second layout surface of the printed circuit board 30 opposite to the first layout surface, cannot be arranged conveniently on the printed circuit board 30. Moreover, since the lead connecting frame 12 is required, the manufacturing cost of the CCD image sensor is increased. Lastly, the manufacturing process of the conventional CCD image sensor is complicated due to the need to prepare an image sensor IC package before mounting the IC package on a printed circuit board.